1. Field of the Invention
The present invention relates to a keyboard apparatus having a key frame to which is mounted a key unit that includes a plurality of key main bodies supported via hinges for pivotal motion by a common base end.
2. Description of the Related Art
Conventionally, there has been known a keyboard apparatus in which a key frame is mounted with a key unit having a plurality of key main bodies supported for pivotal motion by a common base end via thin plate-like hinges. For example, Japanese Patent No. 2628656 discloses a key unit comprised of two white key units and one black key unit, which are disposed in a stacked relation. The white and black key units each have hinges horizontally extended rearward substantially parallel to key depression surfaces of the keys, and therefore, these key units are long in size in a longitudinal direction of keys. As a consequence, the keyboard apparatus is large in depth size.
On the other hand, Japanese Laid-open Patent Publication No. 2001-215968 discloses a key unit in which hinges and a common base end are vertically extended downward from rear parts of key main bodies, thereby reducing the size of the key unit in the longitudinal direction of the keys.
However, in the key unit disclosed in Japanese Laid-open Patent Publication No. 2001-215968, the common base end is fixed at a plurality of portions to the key frame using screws. This poses a problem that many man-hours are required in mounting the key unit to the key frame and the number of component parts increases. When mounting the key unit to the key frame, an operator ordinarily performs an operation of placing the key unit in a desired position from the front side of the keyboard apparatus. Nevertheless, the keyboard apparatus disclosed in Japanese Laid-open Publication No. 2001-215968 is constructed to threadedly engage screws from the rear side of the keyboard apparatus, which requires an additional step of such as inverting the keyboard apparatus front to back, posing a problem of poor workability.